I would like to tell you that it does everything but unfortunately Android is missing a few features. Email, Calendar, and Contact synchronization will be excellent on almost all Android devices. However, most will be missing Task and Notes synchronization with Outlook.
I use my device for a mix of work and personal, even though I do have a BlackBerry (right now) dedicated to work use, and find that I really would miss those two extras were I to give up the BlackBerry. If your mother does not use Tasks or Notes she will be at no disadvantage by switching to a good Android device and there are work-around options available to fill the gaps.
Also, the Galaxy S II and likely the Galaxy S III offer Notes and Task applications that synchronize properly with Outlook through Exchange, just as they should. This is something Samsung has added as a part of their TouchWiz UI. I'm not aware of any other Android phones that offer these without the user needing to add new applications from the market that often don't sync with Outlook directly.